David Cameron went into the chamber with an open goal on Labour’s policy and credibility, provided by Ed Balls this week. He largely ignored it, and booted the ball in an entirely different direction.

The PM’s main line of attack was over child benefit. We learned today that Labour would (probably) not repeal the Coalition decision to take child benefit away from higher earners.

This is what is known in the trade as a U-turn, since Labour had previously suggested that it might reverse the cut.

The apparent shift in Labour position, Mr Cameron said, is a scandal, a sign that the Opposition are a bad lot who couldn’t run a whelk stall, or words to that effect.

This is where I get confused. Mr Cameron has cut child benefit. He says that doing so is both right and popular. Now Labour suggests that it would do the same thing, and Mr Cameron suggests that this is a bad thing.

Now, I know the Tory thinking here: the idea is to persuade voters that Labour are an inconsistent shower and make Ed Miliband’s party pay the price for years of empty opposition and policy confusion.

And maybe those allegations are fair. Maybe a Government that had chopped and changed on big questions in such a way would be crucified by nasty scribblers like me.

But here’s the thing: it isn’t the same. Most voters don’t know what Labour’s policy on child benefit has been for the last three years, and haven’t cared either. Most voters are probably unaware of whether Labour has been consistent in its thinking on benefits issues or not. Most voters don’t spend their time pondering the (in)consistency of opposition party policy in the first half of a Parliament. If they did, they might have had more of problem with a party that used to best “share the proceeds of growth". Most voters only start thinking about Labour policy rather closer to the election in 2015.

Perhaps days like this will help focus their attention on such issues. And what will they take away from today? Perhaps it will be the fact that an opposition party whose policies they haven’t paid attention to has changed some if its policies.